Strange numb pain in head

[AJ1200]

Hello.
Here is a quick back story:
I was in a shooting accident 18 years ago. The doctors removed what they could of the bullet fragment and put a plate where the bullet exited my skull. About 8 years ago I started getting seizures from the scar where the bullet penitrated my brain tissue.
There is the question: Reasontly I notived a strange cold numb pressure feeling around that area and around my head plate. I can feel my heartbeat against my head plate and it feels like it want to explode. I had an MRI done about seven months ago and they say that there is nothing wrong except the brain scar and bullet fragments. It gets worse when I breath or put pressure on it. Can you give any advice, because they feeling is very strange and I'm really worried. Thanks